Dùng từ gợi ý viết lại câu sao cho nghĩa không thay đổi: 1) Keeping the environment clean is very important. 2) They will show the time machine to the public when they finish it. 3) He was delighted to receive his aun't letter

Dùng từ gợi ý viết lại câu sao cho nghĩa ko thay đổi 
1, Keeping the environment clean is very important
- It's ....................
2, They will show the time machine to the public when they finish it 
- The time machine ..................
3, He was delighted to receive his aun't letter 
- He was delighted that...............
4, Old car tires are recycled to make shoes and sandals
- Poeple ...................
5, I'm very sad that I wasn't accepted in that group
- I'm very sad not ..............
6, It's three years since I last spoke to her 
- I haven't ..............
7. Tam doesn't type á she used to 
- Tam used ..............
8, " please turm down the radio fir me " said my father